Majid Hashemi

Lead is one of the toxic heavy metals in the environment and its concentration in oceans, seas, lakes and rivers should be controlled. Both hydroxyapatite nanoparticles and gelatin were extracted from the bone wastes of Talang queenfish and were used for preparation of a hydroxyapatite-gelatin nanocompo-site. The nanocomposite was used as a modifier in fabrication of a carbon paste electrode (CPE) for determination of Pb2+ concentration. The behavior of the prepared electrode was studied with respect of changes in the amount of modifier and pH of the solution. The best response was obtained with 5% wt of composite in CPE and at pH 5. The prepared electrodeshowed a linear response in the concentration range of 2–290 μM of Pb2+ with a good detection limit and acceptable stability, reproducibility and selectivity. The modified electrode showed an excellent selectivity towards Pb2+ in the presence of other metal ions such as Cd2+, Cu2+, Hg2+, Fe2+, Ni2+, Zn2+, Co2+ and Mg2+. The electrode can also be used for simultaneous determination of Cd2+, Cu2+ and Hg2+ without considerable interference with each other or Pb2+ ions. This electrode is convenient for determination of Pb2+ in real water samples without using a pre-concentration step.